A diagnostic description of the genus is given with special emphasis on the occurrence of succulence amongst its species. The geographical distribution is outlined, together with a selection of important literature, and an explanation of the etymology of the name. This is followed by a short summary of its position in the phylogeny of the family and of the past and present classification in a phylogenetic context. The succulent features present amongst the species of the genus are shortly explained as to morphology and anatomy.
This is followed by a synoptical treatment of the succulent species of the genus, complete with typification details, full synonymy, geographical and ecological data, a diagnostic description, and, where applicable, notes on phylogenetic placement and relationships, as well as economic and/or horticultural importance.
Nolina Michaux (Fl. Bor.-Amer. 1: 207, 1803). Type: Nolina georgiana Michaux. — Nolinoideae — Lit: Trelease (1911: synopsis); Walker (2001: introduction); Hess (2002: Fl. N America); Hochstätter (2010: monograph). Distr: S USA (California, Arizona, Texas to Florida), Mexico. Etym: For Abbé P. C. Nolin (fl. 1803), French agriculturalist and horticultural author.
Dioecious (or rarely polygamo-dioecious), acaulescent or arborescent perennial shrubs, stems sometimes basally swollen, occasionally with extensive underground rhizomes; L linear, hard, fibrous, margins rough or serrulate; Inf paniculate, diffuse and racemose, Br subtended by Bra; Ped jointed; Fl usually functionally unisexual; Tep 6, in 2 groups of 3, small, persistent, spreading; St 6, usually abortive in fertile female flowers; Fil short, slender; Ov 3-lobed, sessile or shortly stipitate, abortive in male flowers; Fr papery 3-celled capsules, dehiscent; Se 1–3, globose to oblong.
A genus of c. 30 species. As the genus is here circumscribed, and separated from Beaucarnea (incl. Calibanus), it consists of xerophytic shrubs, not truly succulent, but some species have massive pachycaul stems. Most taxa occur in Mexico, but several species grow across the S USA from California to Florida. Many are poorly known. Gentry (1972) notes that the genus possesses few striking morphological characters, with flowers being monotonously similar and fruits varying only in size and dehiscence. He suggests leaf characters to be the most useful for determining the nature of closely related entities.
Hochstätter (2010) published a synopsis of the genus, which is largely followed here with the addition of more recently described species. He included a key to the 26 species recognised at that time.
In Mexico species have several common names, including “Zacate Cortador”, “Zacate de Armazón” and “Palmilla”. In the USA, species are commonly known as “Beargrass”, and as the name suggests, plants resemble coarse grass when not in flower. Leaves are tough and have been used for thatching, brooms, baskets, hats, mats etc. In the Sonoran Desert, flower stalks of N. beldingii, N. bigelovii and N. macrocarpa are roasted and eaten (Hodgson 2001: 64).
Sect. Nolina (= Graminifoliae Trelease 1911, nom. inval., Art. 22.1): Acaulescent, L thin and grass-like but hard and fibrous, linear, rarely > 0.5 cm wide, rather flat, usually not brush-like at the tip. — 6 spp. (no taxa treated here).
Sect. Erumpentes (Trelease 1911) Hochstätter 2010: L rather thick, linear or narrowly oblong-triangular, to 1.2 cm wide, green, ± concave, tip often fibrous-lacerate; Fr small, not inflated. — 7 spp., of which 2 are included as representatives of this xerophytic but non-succulent group.
Sect. Microcarpae (Trelease 1911) Hochstätter 2010: L rather thick, linear or narrowly oblong-triangular, to 1.2 cm wide, green, ± concave, tip often fibrous-lacerate; Fr moderately sized, somewhat inflated. — 4 spp. (no taxa treated here).
Sect. Arborescentes (Trelease 1911) Hochstätter 2010: Mostly trees or more rarely with underground branching rhizome; L relatively thin, 1.5–4 cm wide, tip usually not brush-like; Fr large, inflated. — 11 spp., all treated here because of their mainly pachycaul habit.
 Arborescent, stem up to 4 m, 15–20 cm ∅, often modestly branched; L arranged into terminal Ros, linear, tapering, to 130 × 4 cm, glaucous-pruinose, deep blue, slightly flexible, tip over 8 cm, dried and intact, erect, pointed; Inf conical, paniculate, 2–3 m, well branched, primary Br 30–60 cm; Fl 4–8 mm ∅, white, highly scented.
Closest to N. parviflora, but differing principally in the larger inflorescence, smaller highly scented flowers, but especially in the deep blue glaucous-pruinose leaves, contrasting with the green leaves of the former species.
N. beldingii Brandegee (Zoe 1(10): 305–306, 1890). Type: Mexico, Baja California (Brandegee 583 [not recorded]). — Distr: Mexico (Baja California: Cape region); 300–1500 m. I: Hochstätter (2010: 34–35).
Incl. Nolina beldingii [?] deserticola Trelease (1911) ≡ Nolina beldingii var. deserticola (Trelease) Trelease (1912).
 Tree, stem 3–6 m, openly branched, with a large crown of stiff L forming Ros; Br 8–10 cm, often again branched with branchlets 1–2 cm; L rigid, erect to recurving, 50–100 × 1–2 cm, flexible, blue-green, margin serrulate; Inf erect, paniculate, 1–2 m × 20–50 cm; Fl 2 × 2 mm ∅, cream; Fr depressed, retuse at the base, 5–10 × 15 mm; Se globose to ovate, brownish, 4 × 5 mm.
This Baja Californian endemic is a small tree, with its type locality in the mountain tops of the Cape Region. Its appearance is similar to N. nelsonii, but the leaves are less rigid. Superficially it looks like Yucca rostrata. It is frost hardy to −10°C.
N. bigelovii (Torrey) S. Watson (Proc. Amer. Acad. Arts 14: 247, 1879). Type: USA, Arizona (Bigelow s.n. [NY, GH]). — Distr: USA (California, Nevada, Arizona), Mexico (Sonora, N Baja California); rocky hillsides and flats of the S Mojave and Sonoran Deserts, 300–1500 m. I: Gentry (1972: 181, fig. 71); Hochstätter (2010: 32–33).
≡ Dasylirion bigelovii Torrey (1857) ≡ Beaucarnea bigelovii (Torrey) Baker (1872).
 Stem 1–3 m with a large crown of stiff L persisting dry and reflexed on the trunk; L linear, 80–120 × 1.5–3.5 cm, tip entire, margins at first serrulate then filiferous; Inf paniculate, 60–100 cm; Bra deltoid-lanceolate, thin, 4–10 × 1–2 cm, attenuate, soon deciduous, primary Br slender, 10–20 cm, ascending, glabrous, smooth; Tep oblong-linear, 2.5–3 mm; OTep introrsely shortly apiculate, reflexed in female flowers; ITep erect or ascending; Fr narrowly emarginate at tip and base, 8–12 × 9–12 mm; Se ovoid to oblong, grey to white-tawny, wrinkled, 2.5–3.5 mm.
This is the most distinctive and widespread member of Sect. Arborescentes. The filiferous leaves are diagnostic. Gentry (1972) anticipated that the taxon should also occur in adjacent Mexico (Sonora) and this range extension has been confirmed (Hochstätter 2010). Common names: “Bigelow’s Nolina”, “Bigelow’s Beargrass”.
N. cismontana Dice (Novon 5(2): 162–164, 1995). Type: USA, California (Dice & Oberbauer 650 [SD 121705, ARIZ, NY, RSA, UC]). — Lit: Dice (1988). Distr: USA (cismontane S California); chaparral on sandstone and shales, 200–1300 m. I: Hochstätter (2010: 43).
 Stem 0.5–1.5 m, with woody caudex, branching above and below ground, mature Ros with 30–90 L; L lanceolate-linear, 50–140 × 1.2–3 cm, base expanded, margin serrulate; Inf 1–3 m, with rather narrow Br 13–35 cm long and spreading; Bra large, papery, persistent; Tep cream-white, ovate, 3–5 × 1.5–2.5 mm; Fr orbicular, papery, emarginate at base and tip, 8–12 mm tall and slightly broader; Se ovoid to oblong, reddish-brown, 4–5 × 3–4 mm. — Cytology: 2n = 38.
Close to N. parryi and for a long time confused with it (Hess & Dice 1995). Endemic to S California, and geographically isolated. It is endangered and threatened throughout most of its range by residential and commercial development. Vernacular names: “Chaparral Beargrass”, “Chaparral Nolina”.
N. excelsa García-Mendoza & E. Solano (Bot. Sci. 90(1): 22, ills. (p. 23), 2012). Type: Mexico, Oaxaca (Redonda-Martínez & al. 481 [MEXU, FEZA]). — Lit: Rivera-Lugo & Solano (2012). Distr: Mexico (Oaxaca: Mixteca Alta); ecotone between oak forests and desert scrub, slopes, 2300–2700 m.
 Tree, stem 8–13 m, 40–50 cm ∅, basally swollen, outer bark fissured, grey-blackish, with 8–16 Br; L linear, (60–) 70–85 × 1.4–2.1 cm, chartaceous, glaucous, apex attenuated, margin denticulate; Inf paniculate, erect, lax, 1.2–1.6 (–2.5) m; Br 12–14 cm; Bra 35–40 × 3–6 cm, lanceolate, appressed, papery; bracteoles 3–9 × 2–5 mm, ovate to deltoid; Fl unisexual; Ped 3.5–4 mm; Tep 3–4 × 1.8–2 mm, free, nearly equal, elliptic to obovate, with apiculate apex, papillate, in male flowers reflexed, concave in female flowers, whitish with a longitudinal median purple stripe; Fr narrowly emarginate at tip and base, 7–8.5 × 7–9 mm ∅, rounded, distally inflated, with thin pericarp; Se subglobose, dark brown, muriculate, 3.5–4.2 × 3–3.8 mm.
This species, with stems up to 13 m tall, is the largest in the genus and hence its very appropriate epithet. Its closest relative is N. parviflora, from which it is distinguished by its greater height, shorter and less glaucous leaves, whitish tepals with the distinct purple mid-stripe, smaller fruits, and in the shape, size and ornamentation of the seeds (muriculate in N. excelsa; reticulate in N. parviflora). Additionally both species flower and fruit at different times. N. excelsa is endemic to a small region E and N of Huajuapan. It is known by the name “Sotol”. The leaves are used to thatch roofs of houses.
 Tree-like, stem to > 6 m, 25 cm ∅, basally swollen, modestly branched; L linear, tapering to 120 × 4 cm, pale green, very flexible, with slightly curling tip 15 cm long, dead leaves forming a dense covering of the branches below the terminal rosette; Inf paniculate, >2.3 m tall, elongate, branched, primary Br 15–30 cm; Fl 20 mm ∅, white; Fr and Se not known.
One of the largest and hardiest members of the genus. It is adapted to alpine conditions, where temperatures below −15°C are not infrequent. It grows sympatrically with N. nelsonii, but no hybrids have yet been observed (Hochstätter & Donati 2010).
N. interrata Gentry (Madroño 8: 181, fig. 1, t. 1, 1946). Type: USA, California (Gentry 7330 [SD]). — Distr: USA (S California: San Diego County), Mexico (N Baja California); rocky hillsides, chaparral, 200–700 m; very rare. I: Hochstätter (2010: 44–45).
 Plants with underground branching rhizome to 3 m × 30 cm ∅, above-ground stems not obvious, mature Ros with < 45 L; L linear, glaucous, 70–100 × 0.8–1.5 cm, base barely expanded, tip dry, slender, not filiferous, margin minutely and persistently serrate, armed with denticles of 2 sizes; Inf open compound panicles 1.5–2 m, base of peduncle 0.5–1.8 cm ∅; Bra persistent, 20–40 cm; female Fl with staminodes inserted on the Tep; Fr large, broader than long, 12–15 mm wide; Se reddish-brown to yellowish, wrinkled, 5 × 4 mm.
Distinguished by the glaucous leaves with coarse armature. The horizontal underground stem or rhizome is especially noteworthy, but this structure may be present in other species assumed to be acaulescent, since this feature may be readily overlooked. Known locally in San Diego County as “Dehesa Nolina” and “Dehesa Beargrass”. N. interrata is very rare and hence one of the most endangered plant species in California, occurring in only two small stands. The populations are stable but are slowly being affected by land clearance for housing development. Three additional populations are known in Baja California.
N. matapensis Wiggins (Contr. Dudley Herb. 3: 65, 1940). Type: Mexico, Sonora (Wiggins 7515 [DS]). — Distr: Mexico (Sonora, Chihuahua); mountain woodland, gravelly slopes, 900–1700 m. I: Walker (2001: 221, figs. 11–12); Hochstätter (2010: 40).
 Small trees, stem to 3–10 m, basally swollen, simple or modestly branched, bark fissured; Ros small; L linear, 70–120 × 1–1.5 cm, recurved, hard, striate, greenish-yellow, somewhat glaucous, margin finely serrulate; Inf paniculate, 1.5–3 × longer than the L, primary Br 15–35 cm, branchlets 10–15 cm; Tep oblong-linear, 2 mm; Fr broadly ellipsoid, depressed, deeply notched at both ends, tardily dehiscent, 8–9 × 5 mm; Se pale brown, nearly globose, 2.5–3 mm ∅.
This species has a narrow distribution range. The leaves are used for basket-making, the stems for posts. A relatively unknown species, first introduced into cultivation in 1976 as ISI 982. Plants from this introduction are now multi-headed specimens at the Huntington Botanical Garden. The species is recommended as an attractive landscape plant for subtropical areas such as S California. Local vernacular names: “Palmito”, “Tuya”.
N. nelsonii Rose (Contr. US Nation. Herb. 10: 92, 1906). Type: Mexico, Tamaulipas (Nelson 4489 [US]). — Distr: Mexico (Tamaulipas), dry bush, 1200–2500 m. I: Hochstätter (2010: 39).
 Tree, stem to 4.5 m, openly branched, with a large crown of stiff L forming small Ros; L rigid, erect to recurving, 50–70 × 3–4 cm, flexible, blue to blue-green, margin serrulate; Inf erect, paniculate, 2–3 m × 20–60 cm; Bra scarious, lacerate; Fl 3 mm × 3 mm ∅, cream; Fr papery, 8–10 mm ∅; Se globose to ovate, brownish, 2–3 mm ∅.
This is a small tree similar to N. parryi, but the leaves differ in size and form. Superficially it looks like Yucca rostrata. Reported as frost hardy to −12 °C.
≡ Nolina bigelovii var. parryi (S. Watson) L. D. Benson (1945) ≡ Nolina bigelovii ssp. parryi (S. Watson) E. Murray (1983); incl. Nolina parryi ssp. parryi; incl. Nolina parryi ssp. wolfii Munz (1950) ≡ Nolina bigelovii var. wolfii (Munz) L. D. Benson (1954) ≡ Nolina wolfii (Munz) Munz (1974) ≡ Nolina bigelovii ssp. wolfii (Munz) E. Murray (1983).
 Arborescent, stem 1–2 (–6) m, basally branching, mature Ros with up to 200 L; L linear, 50–150 × 2–4 cm, almost pungent, rather thick, concave, keeled, margin serrulate-scabrous, base strongly expanded; Inf to 4 m, with rather narrow Br 15–30 cm long and spreading, densely flowered branchlets < 4 cm; Bra large, papery, persistent; Fl large; Tep 4 mm, creamy-white; Fr very large, orbicular, deeply notched at both ends, 12–15 mm ∅; Se reddish-brown, 4 × 3 mm.
N. parryi is differentiated from N. cismontana by the taller stems, larger number of leaves per rosette and broader leaf bases (Dice 1988, Hess & Dice 1995). It is endemic to California. Mitich (1982) records spectacular specimens in the Kingston Mountains, Mojave Desert. Here some individuals reach a height of over 6 m with stems 1 m ∅, and with leaves 1.5 m long; the plants are 4 m across. Inflorescences are enormous too, being 4 m long with the fertile portion 2 m in length. He reports that N. parryi grows readily from seed, requiring a mild climate for outdoor cultivation. In such conditions plants flower after 7–8 years. Common names: “Parry’s Nolina”, “Giant Nolina”.
N. parviflora (Kunth) Hemsley (Biol. Centr.-Amer., Bot. 3: 372, 1884). Type: Mexico, México (Humboldt & Bonpland 4031 [P]). — Lit: McVaugh (1989: 242–244, with ills.); Rivera-Lugo & Solano (2012); Ruiz-Sanchez & Specht (2013); Ruiz-Sanchez & Specht (2014). Distr: Mexico (Chihuahua?, Durango, Zacatecas, Nayarit, Jalisco, Michoacán, Querétero?, Hidalgo, Mexico, Puebla, Veracruz, Oaxaca); widely distributed in the pine forest, pine-oak-juniper forests, xerophytic scrub and tropical dry forest localities of the Trans-Mexican Volcanic Belt, Sierra Madre Occidental, Sierra Madre Oriental and Sierra Madre del Sur mountain ranges: steep slopes, mountainsides, barrancas, sandy or rocky soils, 1300–2400 m. I: Rowley (1990: figs. 1–2, 4, as N. longifolia); Folsom & al. (1995: 104–105, as N. longifolia); Hochstätter (2010: 36; 41–42, as N. longifolia).
≡ Cordyline parviflora Kunth (1815) ≡ Dracaena parviflora (Kunth) Willdenow (1829) ≡ Beaucarnea parviflora (Kunth) Baker (1872); incl. Yucca longifolia Karwinsky ex Schultes fil. (1830) ≡ Dasylirion longifolium (Karwinsky ex Schultes fil.) Zuccarini (1840) ≡ Beaucarnea longifolia (Karwinsky ex Schultes fil.) Baker (1872) ≡ Nolina longifolia (Karwinsky ex Schultes fil.) Hemsley (1884); incl. Roulinia humboldtiana Brongniart (1840); incl. Roulinia karwinskiana Brongniart (1840); incl. Dasylirion humboldtii Kunth (1844); incl. Nolina altamiranoana Rose (1905); incl. Nolina elegans Rose (1906).
 Arborescent, stem 1–3 (rarely >5) m, swollen at base, with 1–6 Br, bark thick, corky and rough, with a large crown forming Ros of several hundred L; L initially rigid, later flexible, long-attenuate, erect to recurving, ultimately drooping, to 1–1.5 m × 1.5–2.5 cm, broadened to 5 cm at the base, pale green, smooth and ribbed on both surfaces, margin serrulate, tip entire; Inf erect, paniculate, widely-branched, 0.8–2 m; primary Br to 30 cm, spreading; Bra very long and narrow above a dilated base, foliaceous, to 60 cm; Fl very numerous; Tep 2.5–3 (–4) mm, white-creamy or with green-brown midline; Fr globose, 8–12 mm × 8–12 mm ∅; Se ovoid to nearly globose, light brown, 3.5–4 × 3–3.5 mm.
McVaugh (1989) substantially broadened the concept of N. parviflora to include N. longifolia and N. elegans, giving the species a very widespread distribution from (?) Chihuahua S to Oaxaca. In contrast, Trelease (1911) and Hochstätter (2010) maintained their separation. N. elegans has been of uncertain status since its original description by Rose as “probably acaulescent”. Characteristic features of N. parviflora are the short, broad, widely branched panicles with short very showy long bracts and dense, numerous flowers. It is a small tree similar to N. parryi, but the leaves differ in size and form, being generally longer and more flexible in N. parviflora, initially erect, then spreading and drooping. Easily mistaken for Beaucarnea recurvata, but in contrast N. parviflora has a more arborescent habit and the leaves are long, lax, and not significantly thicker at the base. Superficially it also looks like Yucca filifera. Plants flower annually, but there are mass flowering cycles that last up to three years. Bees, wasps and flies are pollinators (Ruiz-Sanchez & Specht 2013). It is surprisingly little-known and seldom cultivated. It is frost-hardy to −10 °C.
N. pollyjeanneae Hochstätter (Acta Succ. 1(1): 7, ills. (pp. 4–8), 2013). Type: USA, Oklahoma (Hochstätter 523.50 [SRP, HEID]). — Distr: USA (Oklahoma); isolated gentle limestone slopes, on dry rocky hills in open woodland 1300 m.
 Low-growing acaulescent spreading shrubs forming dense clumps 1–2 m ∅; L thin, grass-like, quite flexible, 40–80 × 0.2–0.4 cm, deep green, convex at the base then concave, tip fibrous and tapered, upper surface smooth, lower surface rough, margin finely denticulate; Inf paniculate, 40–80 cm, branched, generally exceeding the leaves; Fl 2–3 mm ∅, white to greenish; Fr capsules 3–4 mm ∅, unilocular, light brown to almost transparent; Se globose, 2–3 mm ∅.
Closest geographically and ecologically to the grass-like species N. greenei (not treated here) and N. texana, but endemic to Oklahoma.
N. texana S. Watson (Proc. Amer. Acad. Arts 14: 248, 1879). Type: USA, Texas (Lindheimer 712 [MO]). — Distr: USA (Texas, C New Mexico), adjacent Mexico (?); rocky hillsides (limestone, granite), grasslands and shrublands, 200–2800 m. I: Small (1916); Gentry (1972: 183, fig. 72); Hochstätter (2010: 15).
≡ Beaucarnea texana (S. Watson) Baker (1880); incl. Nolina erumpens [?] compacta Trelease (1911) ≡ Nolina erumpens var. compacta (Trelease) Trelease (1912) ≡ Nolina texana var. compacta (Trelease) I. M. Johnston (1943).
 Low-growing acaulescent spreading shrubs; L narrowly linear, 70–120 × 0.3–0.4 cm, deeply rounded below, margins somewhat serrulate or smooth; Inf paniculate, slender, 30–60 cm, primary Br 10–15 cm; Bra caudate-attenuate, surpassing the branches, dry, yellowish, persisting; Fl 2.5–3.5 mm, white to creamy; Fr 5–7 × 4–5 mm, round-ovate; Se globose, 2.5–4 mm ∅. — Cytology: 2n = 38.
In contrast to other members of Sect. Erumpentes, the inflorescence of N. texana is longer. It has a wide geographical range in the USA, and Gentry (1972) anticipates localities being found in NW Mexico (Sonora). This is one of the hardiest species in the genus and can tolerate temperatures below −20 °C and hence is winter-hardy in Europe. Common names: “Texas Sacahuiste”, “Bunchgrass”.
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